Pneumatic hammer



May 16, 1939. F, H1 BORM PNEUMATIG HAMMER Filed Sept. 16, 1936 PatentedMay 16, 1939 UNITED STATES PATENT FFE 3 Claims.

This invention relates to pneumatic tools, and more especially toportable, pneumatic hammers for drilling.

An object of my invention is to provide a simple, practical andeiiicient device of the character described.

A further object is 'to lprovide an improved form 'of pneumatic hammerof the portable type for drilling and like operations wherein the hammeris automatically set in operation merely by applying the drill or othertool to the work, no levers, plungers or other device being necessary tobe hand voperated in order to start the hammer action.

-Other objects and advantages will appear and be brought out more fullyin the following specii'ication, reference being had'to the accompanyingdrawing wherein:

Fig. 1 is a side View of a tool showing a preferred embodiment of myinvention;

Fig. 2 is a view in central section of the tool shown in Fig. l;

Fig. 3 is a cross section view on the line 3-3 of Fig. 2;

Fig. 4 is a similar cross section taken on the line 4 4 of Fig. 2;

Fig. 5 is a similar cross section taken on the line 5-5 of Fig. 2;

Fig. 6 is a similar cross section View taken on the line 6-6 of Fig. 2;

Fig. 7 is a similar cross section view enlarged, taken on the line I--lof Fig. 2;

Fig. 8 is a detailed view showing the tool holding sleeve and itsassociated member; and

Fig. 9 is an enlarged section, similar to Fig. 2, showing the parts incomplete valve opening position.

Referring more particularly to the drawing, I show a pneumatic hammerdrill I0, having a hammer cylinder portion II, a valve cylinder portionI2 and a U-shaped handle portion I3. the latter being provided with theusual removable hand piece I4, secured thereto by screws I5 and I6. Thehammer cylinder II is provided with a hammer cylinder bore I'I, having areduced bore portion I8, there being a shoulder I9 at the meeting pointof bores I'I and I8. Cylinder `Il is provided with a threaded endportion 20 for reception of a flange plug 2|, by 50 which the `end ofthe cylinder I'I is closed. A spring bore 22 is formed vadjacent boreI8, and a spring shoulder 23 is provided at the base of bore 22 andadapted to provide a seat for one end of a coiled spring 24. Formedadjacent bore 22 is an enlarged bore 25, there being a shoulder 25a fora purpose to be apparent hereinafter. Bore 25 is provided with aninternal threaded end portion 26, for engagement with the reducedthreaded end 21 of a locl'ng sleeve 28. Sleeve 28 has a bore 25 and, atthe threaded portion 2l, a pair of diametrically opposite slots 30 areformed.

A hammer member 3|, cylindrical in shape, extends through andreciprocates in bores I'I, I8 and 22, and is provided with an enlargedcylindrical portion 32, and a reduced cylindrical portion 33. A shoulder35. formed on the enlarged portion 32, is complementary to shoulder i9,these shoulders serving to limit the movements of the hammer member 3lin the hammer cylinders. I-Iammer 3l is provided with an internal bore35 which is closed at one, that is, the outer end, but opening at theother or inner into bore I'I. A small radial drill hole 36 and a pair oflarger drill holes 3l are formed in the haL mer 3I, and serve as inletports for passage of air as will be more fully apparent hereinafter. Avsimilar' pair of ports 38 are provided for exhausting the air from thehammer cylinder. A plurality of outlet ports 39 are formed in the hammercylinder II. The hammer 3! has the usual hammer striking face 40.

A valve operating piston 4I is reciprocable in bore 29 of the lockingsleeve 23, and has a central bore 42, and at its outer end a recess 43the base of which forms a shoulder 44. Member 4I has a cylindrical outersurface 45 adapted to fit loosely in bore 29 and has an enlargedcylindrical portion 46 adapted to t in bore 25. Member 4I is furtherprovided with an inner face 4l which face is adapted for engagement withone end of spring 24, the spring normally being under compressionbetween shoulder 23 and face 41 to normally maintain piston liI awayfrom hammer face lill. The enlarged portion of 46 of member 4I has ashoulder 48 for seating against a corresponding shoulder 49 on thethreaded end 2l of locking sleeve 28 as will be clear from Fig. 8.

I show a tool such as a star drill 59 having an octagonal shank portion5| and impact end surface 52, a reduced portion 53 having one or more atfaces and a shoulder 54 adjacent to the reduced portion 53.

A locking ball 55 is retained in a bore 55 in member 4I, the bore havinga tapering retaining shoulder 5'! and containing a spring 58, the freeend of which bears against the inner surfacev or" bore 29 of lockingsleeve 28. The ball 55 is adapted to hold the drill 56 in the Valve lll, way l2.

operating piston or member 4l, the ball being maintained by spring 58against a flat face of the reduced portion 53 and the shoulder 55 of thedrill. It will be apparent from this construction that the drill will bemaintained in position against turning or dropping out by its ownWeight, although the drill may be removed if pulled away by sufiicientforce.

A pair of pins 59 are secured in recess 60 in the member 4i indiametrically opposite positions and adapted to reciprocate in slots 3i?of the reduced portion 2 of the locking sleeve 28. A collar 6| isintegrally secured to the shank 5l of drill and is adapted to seatagainst shoulder 44 of recess 43. Cylindrical portion 46 of member 4Ihas a V-shaped groove 52, one face portion or edge of which forms aconical portion or cam surface 63, in which groove a ball is adapted torest, ball 64 being further positioned in an aperture 65 formed in apartition wall 6B common to cylinders il and I2.

A valve assembly @l is mounted in valve cylinder i2 having an enlargedvalve stem bore iS, the end of' which is closed by threaded plug 3a.Valve cylinder l2 is further provided with a reduced valve stem bore 69,an air chamber 'l and an intake chamber 1l.

Valve assembly 61 is provided with a stem 'i2 adapted to pass throughbore 69 and a stem eX- tensicn located in bore 5E, the ree end of stemextension 'i3 having a conical portion or cam surface 'lli engageablewith ball Bil. A valve seat 'l5 is formed between chambers 'it and iiand a valve l5 secured to stem 'i2 is adapted to seat on valve seat i5.A spring 'i'i in chamber H bears against an adjustable plug 'i3 andagainst valve "i6 and normally keeps the valve closed on seat l5. A portor air passage 'i9 interconnects chamber 'it with a chamber i formedbetween shoulders I and 3s when separated. A small pocket 8l is formedat one end of chamber 1E and is adapted to hold a packing element 82 forsealing bore 69 and stern 'I2 against leakage of air and a collar 83secures the packing S2 in piace under the action of a spring 84, theends of which seat against collar S3 and the valve "i5, A threadedaperture 85 forms a passageway to chamber 1l for the intake for airsupply conducted from a supply hose 85.

The operation of my invention is as follows. Air under pressure issupplied through hose 86 to air chamber 'EL When the drill or other tool50 is pressed against the surface of material desired to be drilled, theforward or downward l y movement of hammer lil will cause collar l toengage shoulder 14, resulting in a shifting of member il inwardly,whereupon the cam surface 63 will force ball 64 outwardly against camsurface T4 which will shift the valve assembly El and move valve 1G offits seat '15, thus admitting the compressed air into chamber 'iii andpassageway i9 and chamber 83, The pressure in chamber 8G will retractthe hammer 3i until ports 36 and 3? are in communication with passage-This will admit the compressed air into bore S5 and bore Il' and thepressure therein will force the hammer against the tool the iace di?striking against the impact end surface of the tool 5%. During theimpact movement of the hammer 3l, the exhaust ports 38 will open intobore 22 and outlet ports 39 when the ports sli have reached shoulder E3,thus releasing the shoulder in bore il permitting the hammer 3i to beagain retracted under the action of the pressure in the passageway 19and chamber 80, and

the hammer action will be repeated, it being understood that valve G'iis kept open by the cam surface 53 pressing against ball 64, and it inturn presses against cam surface 'i4 of the valve stem extension i3.Thus the hammer will continue operating as long as tool 5t is kept underpressure against the working material.

While I have illustrated and described the preierred form ofconstruction for carrying my invention into effect, this is capable ofvariation and modification without departing from the spirit of theinvention. I, therefore, do not wish to be limited to the precisedetails of construction set forth, but desire to avail myself of suchvariations and modications as come within the scope of the appendedclaims.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

l. An automatic hammer of the character described comprising a hammercylinder, a hammer therein adapted to be reciprocated under fluidpressure, a tool holding sleeve in said cylinder, said cylinder havingan internal outwardly facing shoulder, a spring between the sleeve andshoulder normally moving the sleeve forward, removable guide meanscoasting between the sleeve cylinder to prevent turning of the sleeveand permit limited axial movement thereof, a valve cylinder adjacent thehammer cylinder with a passageway therebetween, a valve having a stem invalve cylinder, a member operable in the valve cylinder' adapted toengage the valve for unseating the same and having a cam surface, therebeing a cam surface around the inner portion of said sleeve formed by areduced portion thereof, and a ball in said passageway adapted tosimultaneously engage said surfaces in opposite directions to open saidvalve when tool pressure is applied against said sleeve and hold saidvalve open during the continued application of' pressure.

2. An automatic tool or" the character described comprising, incombination, an operating cylinder, an operating member constructed andarranged to reciprocate in said operating cylinder, valve assemblycomprising a valve and a Valve stem adapted to operate and open saidvalve, a conical portion on said operating member, a cylindricai portionon said operating member adjacent said operating member conical portion,a conical portion on said valve stem, and an intermediate meinberadapted to engage both said conical portions and also said cylindricalportion subsequent to action by said operating member conical portion,whereby said valve is held in open position during Operation of saidtool.

3. An automatic tool of the character described comprising, incombination, an operating cylinder, an operating member constructed andarranged to reciprocate in said operating cylinder, a valve assemblycomprising a valve and a valve stem adapted to operate and open saidValve, a conical portion on said operating member, a cylindrical portionon said operating member adjacent said operating member conical portion,a conical portion on said valve stem, and an intermediate ball bearingadapted to engage both said conical portions and also said cylindricalportion subsequent to action by said operating member conical portion,whereby said valve is held in open position during operation of saidtool and during reciprocation of said operating member.

FERDINAND H. BORM.

